netdev - Re: [PATCH net-next v2 3/5] sock_diag: allow to dump bpf filters

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <5178EB2C.6070709@6wind.com>
Date:	Thu, 25 Apr 2013 10:37:00 +0200
From:	Nicolas Dichtel <nicolas.dichtel@...nd.com>
To:	Eric Dumazet <eric.dumazet@...il.com>
CC:	netdev@...r.kernel.org, xiyou.wangcong@...il.com,
	davem@...emloft.net
Subject: Re: [PATCH net-next v2 3/5] sock_diag: allow to dump bpf filters

Le 24/04/2013 18:22, Eric Dumazet a écrit :
> On Wed, 2013-04-24 at 17:52 +0200, Nicolas Dichtel wrote:
>> This patch allows to dump BPF filters attached to a socket with
>> SO_ATTACH_FILTER. In other words, users allowing to open netlink sockets can
>> see filters set on a socket (when the diag module of the socket family is
>> loaded).
>
> To my knowledge, opening netlink sockets is not restricted.
>
> I do not want user lambda being able to see my BPF filters.
>
> I am root, and was assuming user lambda could not spy on me.
>
> $ cat /proc/net/packet
> sk       RefCnt Type Proto  Iface R Rmem   User   Inode
> 0000000000000000 3      10   0003   3     1 0      0      1089989
> 0000000000000000 3      10   0003   2     1 0      0      1050535
> 0000000000000000 3      2    888e   3     1 0      0      1041970
>
>
> With this information, it seems safe enough, but the whole BPF could
> give interesting ideas to user lambda.
I agree. But then you just have to avoid loading the module packet_diag. This 
module already give some clue to users, because it sends the socket pointer 
through netlink.
Maybe I'm wrong, but I was thinking that this module is used for debug purpose.
If the module is not loaded, my patch has no effect on the system.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html